Journal of East China Normal University(Natural Science) ›› 2020, Vol. 2020 ›› Issue (1): 58-66.doi: 10.3969/j.issn.1000-5641.201922002

• Physics and Electronics • Previous Articles     Next Articles

Atomic distortion in CrN: A first-principle investigation

WANG Qianqian, ZHAO Zhenjie, LI Xin, XIE Wenhui   

  1. School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
  • Received:2019-01-22 Published:2020-01-13

Abstract: First principle calculations indicate that Cr and N atoms in the orthorhombic phase of CrN (Chromium Nitride) tend to shift from their ideal positions along the [100] direction. This shift can induce zigzag Cr-N-Cr chains in the orthorhombic phase; these atomic distortions have not been taken into account in previous studies. The atomic distortions may decrease the total energy of the orthorhombic phase by 0.125 eV/formula unit and make the structure more stable. Lattice constants, moreover, may also be in better agreement with experiment results when considering these atomic distortions. Further, the bulk modulus K0 decreases significantly when considering the atomic distortions and is closer to the experimental value. The atomic distortions are induced by the asymmetric magnetic forces between asymmetric magnetic layers in the special antiferromagnetic order of the orthorhombic phase, which compensates for the magnetic forces between the layers. The atomic distortions would not change the Mott-insulator property of the orthorhombic phase but may reduce the band gap slightly.

Key words: CrN, atomic distortion, magnetic properties, electronic structure

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